Periodization Simplified

“Simplicity is the ultimate sophistication.”
-Leonardo Da Vinci

I am currently reading what I consider to be one of the best books on training theory and practice that I have ever put my hands on. If you knew just how many books on these topics that I have put my hands on over the years, this is no small feat! Surprisingly the subject of the book is neither swim, bike nor run training. It is a book on strength training: Practical Programming for Strength Training (Rippetoe and Kilgore).

Now, before you get up on your specificity high horse, hear me out on this one. There is much that we can learn from the world of strength training. Because it is such a numbers focused activity with years and years of folks experimenting with different methods and quantifying results, it is well ahead of the game when compared to the relatively new quantitative additions to endurance sports (power meters, pace meters, etc). Furthermore, stress is stress. Selye’s General Adaptation Syndrome is called “General” for a reason. Our response to stress, whether that stress comes from lifting a heavy barbell or from running a bunch of miles has many similarities. Sure the timing and the nature of the adaptive response may be a little different but the process is fundamentally the same.

And so, I find myself devouring this book with some serious gusto. The reason being, this book takes a new and unique look at one of my favorite subjects in exercise prescription — periodization.

No, Kilgore and Rippetoe don’t add another term to the already confusing list of mesocycles, macrocycles and microcycles. Rather, they simplify all of these terms by bringing them all back to the only cycle that counts: The Adaptation Cycle.

As Selye observed way back when, when an organism is exposed to a stress it goes through stages:

  • Alarm: Performance ability is temporarily reduced as the individual is exposed to stress.
  • Resistance/Adaptation: The organism “rallies” and its ability to tolerate the next exposure of the stressor is improved.
  • Exhaustion: If exposure to the stressor is too frequent or strong to allow for adaptation, the organism will be depleted of its energy or “adaptation reserve.”

While this concept is expressed theoretically, in the world of athletic training it is very measurable. The criteria for successful adaptation is that the organism should be able to cope better with the stressor on its next exposure. If not, either the stressor was insufficient or the stressor was too great. Both of these scenarios can be tested…

1) Does the athlete improve performance from one session to the next?

Since most of you reading this are probably advanced athletes or coaches dealing with relatively advanced athletes, this may appear a bit of a dumb question. “Of course not,” you say, “we can’t expect an athlete to improve from one session to the next.” Yet, this is exactly what happens when we expose someone who is extremely deconditioned to regular training. But, for our population, the answer to this question is generally no. So this brings us to question 2…

2) Is the athlete able to perform at a higher level than they started after the stressor is removed?

This is a relatively simple matter of testing (re-exposing the athlete to the initial stressor) at the end of a cycle. If the answer to this question is no, then either the stress was insufficient or excessive.

Generally if performance is worse than initial exposure, the latter is true. If performance is approximately equal to initial exposure, the former is true.

While much has been written regarding the first scenario (overtraining), less attention has been paid to the second scenario — “undertraining.”

In order to cause an adaptive response to be initiated, homeostasis must be adequately disturbed in a way specific to the adaptation sought (in endurance training, usually a way that significantly challenges cellular aerobic metabolism).

The level of specific “damage” that elicits an adaptive response in endurance athletes has been studied quite extensively (and often accidentally) via overtraining studies (such as Verde et al., 1992, Hedelin et al., 2000). In general, these studies have shown that increases in cortisol of 10-30% for a short loading period induce an adaptive response providing recovery is allowed. When adaptation begins to fail (the load is becoming too great or prolonged), cortisol reduction in response to load is blunted and signs of parasympathetic over-reaching begin to occur, such as decreases in maximal power of 5-10%, decreases in submaximal endurance of 30-50%, decreased response to orthostatic stress, decreased HR response of 3-7% for a given workload begin to surface.

The amount of actual training stress that it takes to reach this level of disturbed homeostasis varies greatly with the fitness of the athlete and thus the length of the loading cycle. This is the crux of Kilgore and Rippetoe’s periodization approach.

While one exposure to a novel stressor may be sufficient to disrupt a novice’s homeostasis to the point of instigating an adaptive response, for an advanced athlete it takes more. A lot more.

In the context of daily training, an advanced athlete runs out of gas before they can damage themselves to the extent required to significantly disrupt the system. Therefore, within a loading cycle it becomes a sequence of ‘beat down’ until the athlete runs out of energy, go away and restock energy then come back and resume the “beat down.” This isn’t an adaptive cycle as the athlete doesn’t rest long enough to begin the repair process, merely long enough to restock the energy stores ready for the next “beat down.” Thus, the cumulative effect of loading stressors (rather than the magnitude of each stressor) becomes more important for the advanced athlete.

A novice, on the other hand, is able to damage themselves significantly before running out of energy so the adaptive cycle occurs after each exposure to stress; over a course of days rather than weeks. Thus session to session improvement or “linear loading” is an effective strategy. In fact, when it is no longer an effective strategy, the athlete can no longer consider themselves a novice in the sport and longer, more complex cycles (that focus on cumulative damage) must be instigated for further improvement to occur.

This simplified form of periodization — a progression of cycle length as the athlete advances in ability can be related to Selye’s General Adaptation Curve as shown below.

Novice: Short adaptation cycle (48-72hrs)
Intermediate: Medium adaptation cycle (1-2 weeks) In traditional terms, a “microcycle”
Advanced: Long adaptation cycle (>1mth), in traditional terms, a “mesocycle”

I admit, after reading the above, “simplified” may be a bit of a stretch, but hopefully this piece will facilitate the move from arbitrary traditional loading:unloading cycles to cycles that are more specific and customized to the needs and recovery abilities of the individual athlete.

Train Smart

Categories: Training

About Author

Alan Couzens

You can contact Alan at